CHAPTER I. 



GENERAL ACCOUNT OF MISSOURI DEVONIAN. 



The Paleozoic in Missouri is represented by formations 

 belonging to Cambrian, Ordovician, Silurian, Devonian, Mis- 

 sissippian, and Pennsylvanian periods. The generalized geologi- 

 cal column on page 1 gives average thicknesses of the various 

 formations in northeastern Missouri where all periods are 

 represented. The Devonian is the subject of treatment in this 

 volume. 



From Marion County in the northeastern part of the State 

 to Pettis County west of the center nearly all of the numerous 

 Devonian outcrops were investigated and form the basis for 

 the discussion in this chapter. Limited outcrops of Devonian 

 rocks occur in the southeastern part of the State, chiefly in 

 Ste. Genevieve County. In Chapter II the author has described 

 the fauna of the middle Devonian of this region while Chapters 

 on the Bailey limestone by V. 0. Tansey and on the Little 

 Saline limestone by Grace Anna Stewart describe the general 

 fauna of the lower Devonian. 



In Pennsylvania, Maryland, New York, and Virginia 

 Devonian deposits are several thousand feet thick; in Ohio they 

 reach a thickness of 2,000 feet or more; but they thin westward 

 and no section in central Missouri is more than 100 feet thick. 

 Moreover, in eastern United States the Devonian consists 

 mainly of sandstones and shales, while in central Missouri it is 

 mainly limestones. 



In New York, the type region for Devonian in America, it 

 consists of several formations grouped into Lower, Middle, 

 and Upper, and all divisions are well represented, while in 

 central Missouri the Lower Devonian is not represented, al- 

 though present in the southeastern part of the State. The 

 formations in other states are given in the following table with 

 their equivalents in Missouri: 



(i) 



